Hi Joseph, On Tue, 2015-11-17 at 15:55 +0000, Joseph Myers wrote: > On Tue, 17 Nov 2015, kbuild test robot wrote: > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git test > > head: e37d8480fbd6b9ad3665ac85a903098413ba67ae > > commit: 71fa67f178c6c3c338d0b99644bce808f2f0965e [7/8] sparc/math-emu: Move sparc from math-emu-old to math-emu > > config: sparc-defconfig (attached as .config) > > reproduce: > > wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross > > chmod +x ~/bin/make.cross > > git checkout 71fa67f178c6c3c338d0b99644bce808f2f0965e > > # save the attached .config to linux build tree > > make.cross ARCH=sparc > > > > All errors (new ones prefixed by >>): > > > > In file included from arch/sparc/math-emu/math_32.c:77:0: > > > > include/math-emu/quad.h:72:1: error: unable to emulate 'TF' > > typedef float TFtype __attribute__ ((mode (TF))); > > Is this with a compiler that defaults to -mlong-double-64 (which is, I > think, now an unusual configuration on SPARC - it might arise for > bootstrap compilers, but any normal distribution compiler should default > to -mlong-double-128)? FWIW this built OK with my sparc compiler which is 4.6.3, I don't know what compiler the robot is using: http://kisskb.ellerman.id.au/kisskb/buildresult/12549136/ > If so, the old code would have been quietly building with a union that > contains the "wrong" long double type, when using such a compiler. And > actually I think that because of the particular subset of macros used, > this would have worked; the long double member of the union wouldn't have > been used in this code. > > My inclination would be to use > > CFLAGS_math_32.o = -mlong-double-128 > CFLAGS_math_64.o = -mlong-double-128 > > in arch/sparc/math-emu/Makefile to fix this properly (the "unable to > emulate" error is for modes that fail GCC's scalar_mode_supported_p hook, > which by default allows the modes for all standard types, hence an error > for -mlong-double-64 when TFmode isn't used by a standard type). Untested > incremental patch follows. > > Signed-off-by: Joseph Myers <joseph@xxxxxxxxxxxxxxxx> > diff --git a/arch/sparc/math-emu/Makefile b/arch/sparc/math-emu/Makefile > index 825dbee..6df8769 100644 > --- a/arch/sparc/math-emu/Makefile > +++ b/arch/sparc/math-emu/Makefile > @@ -5,4 +5,9 @@ > # suppress all warnings - as math.c produces a lot! > ccflags-y := -w > > +# Emulation of quad instructions requires -mlong-double-128 for > +# __attribute__ ((mode (TF))) to be accepted. > +CFLAGS_math_32.o = -mlong-double-128 > +CFLAGS_math_64.o = -mlong-double-128 > + > obj-y := math_$(BITS).o Thanks. I'll take this patch for now and repush the branch to see if it fixes the build error. I cobbled together a commit message which is hopefully vaguely correct: sparc/math-emu: Use -mlong-double-128 The updated math-emu code requires -mlong-double-128 in order to compile, otherwise on some compilers we see errors: In file included from arch/sparc/math-emu/math_32.c:77:0: include/math-emu/quad.h:72:1: error: unable to emulate 'TF' typedef float TFtype __attribute__ ((mode (TF))); Add -mlong-double-128 in arch/sparc/math-emu/Makefile to fix this properly (the "unable to emulate" error is for modes that fail GCC's scalar_mode_supported_p hook, which by default allows the modes for all standard types, hence an error for -mlong-double-64 when TFmode isn't used by a standard type). Signed-off-by: Joseph Myers <joseph@xxxxxxxxxxxxxxxx> cheers -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
